Limited-slip differentials have been developed that use a hydraulically actuated clutch to limit differential rotation between the output shafts of the differential. Such limited-slip differentials can include a pump in the form of a gerotor incorporated into the differential housing. Solenoid valves have been used to precisely control the actuation pressure provided to the clutch. However, to be operable, such valves require an electronic controller and valve control hardware/software. Example limited-slip differentials are disclosed at U.S. Pat. Nos. 4,012,968; 5,310,388; 6,332,522; 6,733,411; 6,789,657; 7,361,144; 7,448,482; and 8,043,184.
A plenum housing is a common metal (e.g. aluminum) component provided on differential assemblies. A plenum housing typically features a low pressure in-feed and a high pressure control. Such plenums generally supply low pressure fluid (under vacuum) to an integrated pump in the differential and feature a high pressure passageway from the pressurized actuator cavity in the differential. The plenum can also retain a valve which regulates the pressure of the differential system.